As disclosed, e.g., in U.S. Pat. Nos. 4,482,669 (Seyferth et al.) and 4,771,118 (Takamizawa et al.) and in Zoeckler et al., Journal of Organic Chemistry, Volume 48, pp. 2539-2541 (1983), and Blum et al., Organometallics, Volume 5, No. 10, pp. 2081-2086 (1986), it is known that organosilazanes are useful in the synthesis of organosilazane polymers and that they can be prepared by reacting an organohalosilane with ammonia in an organic solvent at a temperature in the range of 0.degree. C. to -20.degree. C.
It has now been discovered that the molecular weights of polysilazanes synthesized by the polymerization of such organosilazanes are dependent on the molecular weights of the organosilazanes as well as on the polymerization time and that the use of a lower molecular weight organosilazane necessitates a longer polymerization time to achieve a desired polysilazane molecular weight. It would therefore be desirable to find a means of increasing the molecular weights of organosilazanes prepared by an ammonolysis reaction.
Copending application Ser. No. (374,058) (Balasubramanian et al.), filed June 30, 1989, teaches that temperatures higher than 0.degree. C. can also be used for the ammonolysis of organohalosilanes and that the use of temperatures in the range of about 15.degree.-20.degree. C. leads to an increase in the molecular weights of the organosilazane products.